Pneumatic tool.



Patented Feb, 27, 1912. B

[N VEN TOR PVITNESSES Home .29 vide means for cushioning the valve insuch a manner that the some. will start and stop I, UNITED.ermine-PATENT OFFICE.

JOHN J. PADBURY,

F MCKLAND,'MAINE, ASSIGNOR TO LIVINGSTON MANUFAC- TURING COMPANY, OFROCKLAND, MAINE ,PNE MATIC TOOL.

Specification 01. Letters Patent. I Patented Feb. 27, 1912 "12; at! itconcern Beit'known that 1, JOHN J. PAnnonY, a

citizen of the United States, residing at Rocklend, county of Knox,State of Maine,

liave. -invent ed certain new and useful l npro've'inrien'ts inPnenmatlc Tools, of wh ch .i the 'iiollo'wing is a specificat on,reference hei'ng htid therein to the accompiinying drawing.

This invention relates to ce'rtiiin new and. 'useful improvements 1npneumatic harry niers, and more particularly to pneu'matlc chippingtools, the object-being to provide steel in which the initial movementof the pistqnin its upend down stroke is gradual, caused by the reducedpressurearea of the respective ends of the piston which prevents ithe'jerking and vihratir'igof the tool to a great extent.

Another object of the invention is to pro-- 4 gradually' whereby thepounding of the diflieulties now existing with pneumatic toolsw'valveiis prevented in order to inereasethe lifefof the some and therebyovercome the A further ohjtiet of the invention is to provide a.reversible piston in order to allow the sameto be reversedwhen theimphct portion becoines worn, thereby; increasing the life of the'pistontwo-fold.

A still' further object of the invention,

to provide a pneumatic tool which is ex- I ceedingly simple and cheepinconstructionand one iii-which the parts are so mounted thiit they may heeasily and quickly taken f ap rt, and one which very; strong andposition; Fig. 2'is a; 51

50. gagement with the shank (if a c pping tool;

durable, the parts being so"- 'conn ected' that all danger of the samework ng loose, while in (ring-ration, is prevented.

Othei imd further oh ects'hnd advantiiges of the invention will hehereinafter set forth und the novel features thereof defined by the'tippei ded claim.

In the v'drawing-Figure .l. is a longitudinal sectional elevationthreugh myjniprqved pneumatic tool shownigrlgi e piston in raised and:Fig.'3' is an elevationqmrtly in section of the valve detached.

Like numerals of reference refer to like plirts in the several figuresof the drawing.

formed'in theviilv'ejhl0ek,-the?uppe1r end of a r 'view showingApplication filed June 26, 1911. otta). No. 835,378.

tion 7 of a handle 8 which is provided with a chamber, in which is',.mounted a valve block 10 ivhiehhe'ers against a cylindercap 11 asclearly shown and locked in position by pins .12, only one of which isshown.

The handleisprovi'ded with en inlet passage 13 to which is connected aSupply pipe 'l-l for supplying the-motive fluid, said pas- 5 sage 13communicating with a chamber 15 formed in the valve block in which ismounted a valve 16 lowing ends'lf sndllS of difi'er rntisizesforriiingdifierent: pressure areas, and a central annular passe e'fo ipurpose later-described. .The'end-I oft e vel've is provided with. aprojection 19Jwhich c'o-ects with a chamber 20 formed in. the cover 11'in order to'coshionthe valve on its'dovm stroke which also -redijces-'the pressure ares 5 on the initial movementof the valve inorder 'toreuse the sagne tolmov'e 'slflwly uptil the projection leaves hechamber? v Extending loniti inally throughthe vided with Sorts EQ-uhd.23, the n perend of the passage communicating iii/"it :a pas Stage 24lending into the vnlvejchamher 15 and through which motive flll'id fifiadiip ted to pass and-act upon-the enlarged ress'ur'e v 5 nreaof theyalve in. order torelsejt e some.

In the opposite wall of theffvlinder', a pessage 25 1S formed which isprovidedfwith s 'portQt} 'communicetingwith. th cylinder hnd at-itslupirend reEisterswitliepessage 217 extending throng the cylinder cover.-which, in turn, registers wlthxe 'pessage 28 said-passage registeringwith the inlet pa sage 13 formed"'n't hehandle in 'orde ;m allow motivefluid tobe supplied tug-the cylinder.

Mounted some the cylinderjis I 29 provided with reduced ends'30, one of.

which forms an impact portion' adopted to shown in Fig l. A formed inthe valve block which communiimpact the end of the shank 4 of the tool 5said curl fitting snugly within the reduced Jgvrtien of the cvlincier asclearly shown in ig. .2, and it will be seen thatby this construction,the piston can be reversed inorder to bring the opposite end intoposition to impect the tool. The upper reduced portion of-the pistonenters a chamber 31 formed in the cylinder cover in order to cushion theup stroke of the piston and communicating with the chemher 31 aredivergingpassages 32 which register with passages 33 leading into thevalve chamber in the valve block ami through which live steam or air isadopted to be admitted when in the position shownin Fig. 2 and throughwhich the steam or air is-eilapted to be exheustedus Au exhaust passage34 is notes with achernber 35 surrounciin the valve hlock and isprovided with an ex aust port 36. The cj'iinrle-r is provided with anexhaustport 37st its lower enci through. which the motivefiuid isexhausted on the ilown stroke of the piston. An annular groove formedcentrally in; the piston 29 orming e geese-age which registers withtheis supplieti \nrough the pipe 14, which iney' he provided with ethrottle if desired, into the yassugs 13 and passes into thecylinderthroiigh the port 26 around the groove:

of the piston through the port 23 into the passage 2L A. portion of thefluid pressure passes out of the port 22 lii Ader the lower end of thepiston nucl it will be seen that the pressure arse of the piston isreduced by the project-toil being within the'r'educed portion of thecylinder which causes it slow initial movement of the piston and at thesame time air passes into the valve chamber 1.5 Zn the valve blockagainst the large pres sure area of the valve which, likewise, has

piston enters the chamber 31 and forms i cushioning action in order; toreduce the jar as much as possible. are then closedh'y the piston andthe motive fluicl acts upon the reduced urea of the valve and forces thesame into the position shown in Fig. 2 and the inotive fluid passesthrough the passages from the valve chem her into the upper end of thecylinder into the chamber 31 so as to produce it. slow initiul movementwhich is caused by the reduced area of thepiston until it has left thechamber which allows the fluid power to have full pressure upon thepiston in order to cause the "same to im met the shank of The dead n11"within the lower the tool. end of the cylinder is forced out through theexhaust 37 and the operation'is continued which causes a of the piston?"I Having described my invention end set forth its merits what I claimRRCi'TlGSli'B to secure by Letters Patent is,

A pneumatic tool having a cover at one end provided with chenibersin itsinner and outei faces", a piston mounted in said The ports 23 and 26continuous reciprocation cylinder having a reduced portion come-ting"with one of said chambers, and a valve hav ing it reduced portion(Jo-acting i'vit'h' the chamber upon the opposite faceishisuirl cover. 1l v In testimony whereof I nfiiv my sigimture in presence of twowitnesses;

JOHN'J'. PADBURY. Witnesses r GHAS. .SMALLEY; E. H. Lowni

